CVE-2007-0454 in Samba
Summary
by MITRE
Format string vulnerability in the afsacl.so VFS module in Samba 3.0.6 through 3.0.23d allows context-dependent attackers to execute arbitrary code via format string specifiers in a filename on an AFS file system, which is not properly handled during Windows ACL mapping.
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Analysis
by VulDB Data Team • 01/12/2025
The vulnerability described in CVE-2007-0454 represents a critical format string flaw within the Samba file system implementation that affects versions 3.0.6 through 3.0.23d. This issue resides in the afsacl.so Virtual File System module which handles AFS (Andrew File System) file access control lists and integrates with Windows ACL mapping mechanisms. The vulnerability manifests when Samba processes filenames containing format string specifiers within an AFS file system context, creating a scenario where attacker-controlled input can be interpreted as format string directives rather than literal filename characters.
The technical exploitation of this vulnerability occurs through the improper handling of user-supplied data during the Windows ACL mapping process. When Samba encounters filenames with format string specifiers such as %s, %d, or %x within AFS file system operations, the afsacl.so module fails to properly sanitize or escape these characters before processing them in printf-style functions. This misconfiguration allows attackers to inject malicious format specifiers that can manipulate the program's execution flow, potentially leading to arbitrary code execution with the privileges of the Samba service account. The context-dependent nature of this vulnerability means that successful exploitation requires specific conditions related to the AFS file system integration and the particular Windows ACL mapping operations being performed.
The operational impact of CVE-2007-0454 extends beyond simple privilege escalation as it can enable attackers to gain complete control over systems running vulnerable Samba versions. Since Samba typically operates with elevated privileges to manage file access across network shares, successful exploitation could allow unauthorized users to execute arbitrary commands on the host system, potentially leading to full system compromise. The vulnerability affects environments where Samba is configured to support AFS file systems and Windows ACL mapping, which includes many enterprise network environments that require cross-platform file access control. This makes the exploit particularly dangerous in corporate settings where Samba serves as a critical file sharing service connecting Windows and Unix/Linux systems.
Organizations should prioritize immediate mitigation through patching Samba to versions that properly handle format string specifiers in the afsacl.so module, as recommended by the Samba project and security vendors. Additional defensive measures include implementing strict input validation for filenames in AFS environments, disabling unnecessary AFS integration when not required, and monitoring for suspicious filename patterns that might indicate exploitation attempts. The vulnerability aligns with CWE-134 which specifically addresses format string vulnerabilities where format strings are constructed from user-controlled data, and maps to ATT&CK technique T1059.007 for command and scripting interpreter execution. Network segmentation and access controls should be implemented to limit exposure, while security monitoring should focus on detecting unusual file system operations in AFS-mounted volumes that might indicate exploitation attempts.